The title of Clarke's first novel is misleading; Al's ``heroics'' are a vague reference to his tolerating his somewhat off-center parents--``The Capsellas are a real liability.'' (Throughout his narrative, Al indicates his detachment by referring to them only by their surnames.) The boy is deeply concerned with appearing ``normal'' to others, but the fanciful Mrs. Capsella--a writer of romance novels who wears hippy-style clothing--renders this hopeless. It's not until Al accompanies his mother on a visit to her parents, a rigidly structured, conservative, yet quirky pair, that he appreciates Mrs. Capsella as she is. Although the time is the present and the setting a suburban Australian town, Al comes across as a low-key Holden Caulfield. Quietly humorous in places, the book, like The Catcher in the Rye , emphasizes the main character's internal musings, and is more episodic than plot-driven. The pace may slacken occasionally, but the engaging, perceptive Al is a fellow worth knowing. Ages 12-up. (Apr.)